牛津活动衬垫单髁置换术中间隙压力与下肢力线矫正程度的相关性

Correlational between the gap contact force and the degree of lower limb alignment correction in Oxford mobile bearing unicompartmental knee arthroplasty

目的研究牛津活动衬垫单髁置换术(OUKA)中膝关节间隙压力与术后下肢力线的相关性,为预测OUKA术后下肢力线提供参考数据。方法本研究为回顾性病例系列研究。纳入2020年1月至2022年1月中日友好医院骨科关节外科收治的78例接受OUKA手术的患者(92膝),其中男29例,女49例,年龄(68.8±6.9)岁。术中应用自行设计的压力传感器测量膝关节在0°及20°时内侧膝关节间隙的压力,并按术后下肢力线内翻程度分组。应用Pearson相关性分析评估分析间隙压力与术后下肢力线的关系。比较分析不同力线矫正满意程度组间的间隙压力。结果术中测量伸膝0°时的间隙压力为81.7 N±57.8 N,屈膝20°时为96.1 N±54.5 N,术后膝关节内翻角度为2.9°±2.7°。伸膝0°及屈膝20°位时的间隙压力与术后膝关节内翻角均呈负相关(r=-0.493、-0.331,均P<0.001)。各内翻组在伸膝0°时间隙压力的分布不相同,中立位组(n=24)压力[M(Q_(1),Q_(3))]为117.4 N(31.7 N,233.0 N),轻度内翻组(n=51)为63.7 N(11.3 N,209.0 N),明显内翻组(n=17)为31.5 N(8.3 N,87.7 N),差异具有统计学意义(P<0.001);而在膝关节屈曲20°位时,仅明显内翻组与中立位两组间隙压力差异有统计学意义(P=0.040)。力线矫正满意组在0°及20°时的间隙压力均大于明显内翻组,差异均有统计学意义(均P<0.05)。术前合并明显屈曲畸形的患者在伸膝0°及屈膝20°位测得的间隙压力均要大于术前无屈曲畸形(或轻度屈曲畸形)者(均P<0.05)。结论OUKA间隙压力与术后下肢力线矫正程度相关。术后下肢力线矫正良好的患者,术中膝关节在0°及20°的中位间隙压力分别为117.4 N和92.5 N。

Objective To study the correlation between joint contact force and postoperative lower extremity alignment in Oxford unicompartmental knee arthroplasty(OUKA)and provide reference data for predicting the lower extremity alignment after OUKA.Methods It was a retrospective case series study.A total of 78 patients(92 knees)who underwent OUKA surgery from January 2020 to January 2022 in the Department of Orthopedics and Joint Surgery of China-Japan Friendship Hospital were included in this study,including 29 males and 49 females,aged(68.8±6.9)years.A custom-designed force sensor was used to measure gap contact force in the medial gap of OUKA.The patients were divided into groups according to the varus degree of lower limb alignment after operation.Relationship between the gap contact force and the alignment of the lower limbs after operation was analyzed with Pearson correlation analysis,and the gap contact force was compared between patients with different lower limbs alignment correcting results.Results The mean contact force measured during the operation at 0°of knee extension was 81.7 N±57.8 N,and it was 96.1 N±54.5 N at 20°of knee flexion.The average postoperative knee varus angle was 2.9°±2.7°.The gap contact force at the 0°and 20°positions of the knee joint was negatively correlated with the varus degree of the postoperative lower limb alignment(r=-0.493,-0.331,both P<0.001).The distribution of gap contact force at 0°was different in each group,the contact force[M(Q_(1),Q_(3))]of the neutral position group(n=24)was 117.4 N(31.7 N,233.0 N),and it was 63.7 N(11.3 N,209.0 N),31.5 N(8.3 N,87.7 N)in the mild varus group(n=51)and the significant varus group(n=17),respectively,and the difference was statistically significant(P<0.001);while at 20°,only the difference between the significant varus group and the neutral position group was statistically significant(P=0.040).The gap contact force of the alignment satisfactory group at 0°and 20°was greater than those in the significant varus group(both P<0.05).The gap contact force measured at 0°and 20°was significantly greater in patients with preoperative significant flexion deformity than in patients without flexion deformity(or mild flexion deformity)(both P<0.05).Conclusions OUKA gap contact force is related to the degree of lower limb alignment correction after the operation.In patients with well-corrected lower limb alignment after surgery,the median intraoperative knee joint gap contact force at 0°and 20°is 117.4 N and 92.5 N,respectively.